Conventionally, an internal surface of the impeller or turbine shell—the surface for supporting the impeller or turbine blades—is embossed to form one or more slots therein for supporting the blades. It is known to braze impeller or turbine blades to the impeller or turbine shell before the core ring is fixed to the impeller or turbine blades. The process flow of attaching the blades to the shell and core ring can be as follows: (1) blade tabs of the blades are put in shell slots in the shell and then the core ring is placed on top of blades tabs on core ring side; (2) the blades tabs on the core ring side are rolled; (3) the brazing paste is applied along the surfaces of the blade in contact with the shell and the core; and (4) the assembled part—i.e., the shell, the blades and the core ring—is then put through a brazing furnace to complete the brazing process.
U.S. Pat. No. 4,868,365 discloses welding the impeller blades using a laser beam. U.S. Pat. No. 6,237,221 discloses staking the impeller blades to the shell and core ring.